One vertex per element, one color per generator, with an edge from x to x·s.
(1,2,4,6)(3,7,8,5)(17,18,21,19)(20,23,24,22)(26,30)(27,33)(32,36)(35,37)(1,2)(3,7)(4,6)(5,8)(10,13)(14,16)(25,26,29,30)(27,34,33,31)(28,36,38,32)(35,39,37,40)(1,2,4,6)(3,5,8,7)(9,10)(11,14)(12,13)(15,16)(17,19,21,18)(20,23,24,22)(25,26)(27,34)(28,32)(29,30)(31,33)(35,40)(36,38)(37,39)(1,2)(3,7)(4,6)(5,8)(9,11,12,15)(10,14,13,16)(17,20,21,24)(18,22,19,23)(25,27)(26,31)(28,37)(29,33)(30,34)(32,40)(35,38)(36,39)(1,3)(2,5)(4,8)(6,7)(25,28,29,38)(26,32,30,36)(27,35,33,37)(31,39,34,40)A Cayley diagram is a choice, not a fact about the group. Another drawing of this group — in a book, or on a different generating set — may look nothing like this one.